1. Technical Field
Aspects of an example embodiment are directed to an apparatus for melting a solid metal, more specifically, a furnace having an electromagnetic pump for vortex generation to melt a solid metal.
2. Description of Related Art
In related art molten metal processing, scrap may be re-melted to prepare metallic alloys (for example, melting scrap aluminum during manufacturing of aluminum or an aluminum-based alloy) One related art problem experienced during re-melting involves the submerging of small or lightweight scrap particles of metal into the molten metal. Related art furnaces combust organic fuel in one or more combustion chambers located above a metal bath containing solid metal pieces and molten metal. However, a problem exists with these related art furnaces, because many metals, such as aluminum, for example, undergo rapid oxidation when in a solid state and having a large amount of surface area (e.g. swarf, foil, chips and so on).
In a related art metal processing apparatus, a charging chamber used to introduce solid materials into a furnace is connected to the furnace by a pair of pipes. One of the pipes is surrounded by an electromagnetic pumping unit (e.g., pump) that causes molten metal to move through the pipes and circulate between the charging chamber and the furnace. The movement of the molten metal through the charging chamber may help accelerate the melting of the solid pieces. However, the related art pipes, charging chamber, and pump are located outside the furnace.
Thus, this related art metal processing apparatus frequently suffers from solidification of the molten metal within the pair of pipes and, in particular, within the portion of the pipe that is surrounded by the pump. If the temperature of the liquid metal drops below the solidification temperature of the metal within the portion of the pipe that is surrounded by the pump, a blockage can occur. If such a blockage occurs, re-melting of the blockage is hindered by the placement of the pump around the pipe, which prevents direct re-application of heat to the pipe.
Clearing of the blockage in the pipe requires removing molten metal from the furnace; cooling down the entire apparatus; disassembling the pump; and removing, cleaning, and replacing the pipe before the furnace can be returned to operating temperatures. As the metal processing is sensitive to operating conditions, these blockage cleaning steps may result in lost operation time of the metal processing apparatus.
Further, even if solidification due to temperature drops in the pipes does not occur, sedimentary build-up of solid impurities on the pipe walls (known as “dross sedimentation”) of the pipe section surrounded by the pump causes gradual reduction in flow diameter (i.e., pipe narrowing), which can eventually result in blockage of the pump. The placement of pump around the pipe makes cleaning of the pipe section difficult without disassembly of the pump, resulting in lost operation time of the metal processing apparatus.
Alternatively, some related art systems use a mechanical pump instead of the electromagnetic pumping unit. However, if a mechanical pump is used, the mechanical pump must be in contact with the molten metal, which may cause potentially expensive maintenance including frequent replacement of components of the pump that are submerged in the molten metal (such as the impeller, for example).